Administering reversible anesthetic agents empowers the clinician and is desirable for outpatient procedures, but these options must be exercised with considerable caution, skill, and refined clinical judgment.

In human and veterinary patients, acute reversal of opioid effects with a pure opioid antagonist can convert an overly sleepy patient to one that is immediately suffering extreme pain and stress. Gradual reversal by administering reduced doses of an antagonist is possible, but challenging. For partial reversal of opioid sedation, low doses of a mixed-acting agonist/antagonist opioid may be more successful. Patience is warranted in using antagonists because it is easy to go beyond the desired level of reversal, with deleterious results: pain, excitement, and stress.

Reversibility of alpha-2 agonists has led to the well-deserved popularity of this group of sedative-analgesics. The key to success in using alpha-2 agonists in anesthesia is in patient selection—in general they are reserved for use in healthy and exercise-tolerant patients. Many experts would exclude most geriatric patients, and for this geriatric dog with suspected cardiac disease, alpha-2 agonists are not recommended.